package com.example.opengldemo.simple12_03;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import android.opengl.GLES30;

import com.example.opengldemo.util.MatrixState;
import com.example.opengldemo.util.ShaderUtil;

import static com.example.opengldemo.util.ShaderUtil.createProgram;


public class TextureRect 
{	
	int mProgram;
    int muMVPMatrixHandle;
    int maPositionHandle;
    int maTexCoorHandle;
    String mVertexShader;
    String mFragmentShader;
    static float[] mMMatrix = new float[16];
	
	FloatBuffer   mVertexBuffer;
	FloatBuffer   mTexCoorBuffer;
    int vCount=0;   
    
    public TextureRect(MySurfaceView mv,float width,float height)
    {    	

    	initVertexData(width,height);

    	intShader(mv);
    }
    

    public void initVertexData(float width,float height)
    {

        vCount=6;
        final float UNIT_SIZE=1.0f;
        float vertices[]=new float[]
        {
        	-width*UNIT_SIZE,0,-height*UNIT_SIZE,
        	-width*UNIT_SIZE,0,height*UNIT_SIZE,     
        	width*UNIT_SIZE,0,height*UNIT_SIZE,
        	
        	width*UNIT_SIZE,0,height*UNIT_SIZE,
        	width*UNIT_SIZE,0,-height*UNIT_SIZE,     
        	-width*UNIT_SIZE,0,-height*UNIT_SIZE,
        };
		


        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
        vbb.order(ByteOrder.nativeOrder());
        mVertexBuffer = vbb.asFloatBuffer();
        mVertexBuffer.put(vertices);
        mVertexBuffer.position(0);



        

        float texCoor[]=new float[]
        {
            0,0,0,0.642f,1,0.642f,
            1,0.642f,1,0,0,0
        };       

        ByteBuffer cbb = ByteBuffer.allocateDirect(texCoor.length*4);
        cbb.order(ByteOrder.nativeOrder());
        mTexCoorBuffer = cbb.asFloatBuffer();
        mTexCoorBuffer.put(texCoor);
        mTexCoorBuffer.position(0);

    }

    public void intShader(MySurfaceView mv)
    {

        mVertexShader= ShaderUtil.loadFromAssetsFile("simple12_03/vertex_tex.sh", mv.getResources());

        mFragmentShader=ShaderUtil.loadFromAssetsFile("simple12_03/frag_tex.sh", mv.getResources());

        mProgram = createProgram(mVertexShader, mFragmentShader);

        maPositionHandle = GLES30.glGetAttribLocation(mProgram, "aPosition");

        maTexCoorHandle= GLES30.glGetAttribLocation(mProgram, "aTexCoor");

        muMVPMatrixHandle = GLES30.glGetUniformLocation(mProgram, "uMVPMatrix");  
    }
    
    public void drawSelf(int texId)
    {        

    	 GLES30.glUseProgram(mProgram); 

         GLES30.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, MatrixState.getFinalMatrix(), 0);

         GLES30.glVertexAttribPointer  
         (
         		maPositionHandle,   
         		3, 
         		GLES30.GL_FLOAT, 
         		false,
                3*4,   
                mVertexBuffer
         );       

         GLES30.glVertexAttribPointer  
         (
        		maTexCoorHandle, 
         		2, 
         		GLES30.GL_FLOAT, 
         		false,
                2*4,   
                mTexCoorBuffer
         );   

         GLES30.glEnableVertexAttribArray(maPositionHandle);  
         GLES30.glEnableVertexAttribArray(maTexCoorHandle);  
         

         GLES30.glActiveTexture(GLES30.GL_TEXTURE0);
         GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, texId);
         

         GLES30.glDrawArrays(GLES30.GL_TRIANGLES, 0, vCount); 
    }
}
